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p. 69 Element, Compound or Mixture?. An atom is the smallest basic unit of matter. When 2 or more atoms bond together or combine they form a molecule. There are 3 main classifications of matter:. An element is a substance that contains a single type of atom. A compound is a combination
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p. 69Element, Compound or Mixture? An atom is the smallest basic unit of matter. When 2 or more atoms bond together or combine they form a molecule. There are 3 main classifications of matter: An element is a substance that contains a single type of atom A compound is a combination of 2 or more different types atoms that are chemically bonded together A mixtureis made up of 2 or more different types of atoms or substances that do not chemically change or combine.
Pure Substances Element Can not be physically separated Can not be chemically separated Gold is a pure substance (element) that can not be broken down. Each atom of gold is identical, they have the same atomic particles, atomic number and mass Compound Can not be physically separated Can be Chemically separated A compound is a substance made of 2 or more different types of atoms chemically bonded together. Sodium chloride consists of 2 pure substances (elements Na & Cl) bonded together Sodium chloride can be separated or combined using heat 2Na(s) + Cl2(g) → 2NaCl(s)
What is a mixture? Mixtures are a combination of 2 or more substances that do not combine chemically. The different substances of a mixture do not change. Mixtures can be separated by physical means. Vegetable soup is a mixture: carrots and peas don’t mix to make a new vegetable when they are mixed together
Comparing Mixtures and Compounds Mixtures Substances remain the same; no chemical bonding occurs. Can be separated by physical means. Proportions of different substances in a mixture can vary throughout the mixture or from mixture to mixture. Compounds New substances formed by atoms that bond together Can only be separated by breaking atomic chemical bonds. Proportions of different substances in a compound are fixed. The type and number of atoms in a compound are always the same.
Types of Mixtures • Homogeneous mixture - a mixture in which substances are evenly distributed throughout the mixture. (It all looks the same.) • Heterogeneous mixture – a mixture in which pure substances are unevenly distributed throughout the mixture. (The different parts can be seen.)
p. 72 or 73Summary and Study Q • Write a 4 sentence summary. • Write 4 study questions.